In general, a lesion portion shows a color different from a color of a normal mucous membrane tissue. Thanks to enhancement of the performance of a color endoscope device, identification of a lesion portion of which color is slightly different from a color of a normal tissue has become possible. However, in order to become able to precisely identify a lesion portion from a normal tissue based on a slight difference in color on an endoscopic image, an operator needs to be trained under expert's instruction for a long period of time. Furthermore, even for a practiced operator, it is not easy to identify a lesion portion based on a slight difference in color, and therefore careful work was required. For this reason, an electronic endoscope device having the function of executing a color conversion process for highlighting a difference in color with respect to endoscopic image data captured using white light, in order to ease identification of a lesion portion, is proposed, for example, in Japanese Patent Provisional Publication No. 2009-106424A (hereafter, referred to as patent document 1).